From patchwork Thu Apr 11 07:41:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bitao Hu X-Patchwork-Id: 13625551 Received: from out30-99.freemail.mail.aliyun.com (out30-99.freemail.mail.aliyun.com [115.124.30.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8872513E3E5; Thu, 11 Apr 2024 07:41:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.99 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712821306; cv=none; b=PRgsXOd9dmTeneAF6Yo2Mv437P4eVFc9gs1jS/9X61tPjjIPQPfzkkOFYG3Hp/9dYfu/niyuxcOuJrgxfHzkK6K42GPJsdPoSJzdXc1XTJxATq/ARrrwFWcS1srUie91FBDkM/AoK7KGcrtod5vYhqxHIZu/ra2g7KrYcMdOQkI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712821306; c=relaxed/simple; bh=1zRWSXfH24xM+juILZQVIUm8hs+OQD/BWNknxMwOY5s=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=pubOszxV/PhjLLoLAGNjFREoxg+BeMPJMk0XUhoDhNj0HvvPWwHuzZigvtxkuTDIMlxpmhrYUBfTQlTWy9fBBhwmPK2cy6DPyjmIHvOW5ruhRngfSf+e8fA4mb5OMZBWZSYU4+Pb5u+OD7n2OTAgD7mc6Y1Oc2ZhdIFTf7inOpM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=D+Jler6Z; arc=none smtp.client-ip=115.124.30.99 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="D+Jler6Z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1712821300; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=Wy8/fiKaZNwlfMDJNjam2Eo/3fPP4NAAJyni7X89V1A=; b=D+Jler6Ztp91+3u4/OfTg6DMuKQUZr2CTqFk459KGC2GBFS0ro0vNqgkh2HxtwuXHNCv2Skl4/kRkFKs6NuPu6OeaEtq5p3a0UcxEvSzEKZthjzfhc2Q7x6JeLTPYFkvSAhbylL5aCDANLBH9d3xv5bDN5IJof6SP0WEDSMYSoM= X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=yaoma@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0W4KbQ8G_1712821297; Received: from localhost.localdomain(mailfrom:yaoma@linux.alibaba.com fp:SMTPD_---0W4KbQ8G_1712821297) by smtp.aliyun-inc.com; Thu, 11 Apr 2024 15:41:39 +0800 From: Bitao Hu To: dianders@chromium.org, tglx@linutronix.de, liusong@linux.alibaba.com, akpm@linux-foundation.org, pmladek@suse.com, kernelfans@gmail.com, deller@gmx.de, npiggin@gmail.com, tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com, jan.kiszka@siemens.com Cc: linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, yaoma@linux.alibaba.com Subject: [PATCHv13 0/5] *** Detect interrupt storm in softlockup *** Date: Thu, 11 Apr 2024 15:41:29 +0800 Message-Id: <20240411074134.30922-1-yaoma@linux.alibaba.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) Precedence: bulk X-Mailing-List: linux-parisc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hi, guys. I have implemented a low-overhead method for detecting interrupt storm in softlockup. Please review it, all comments are welcome. Changes from v12 to v13: - Update patch #1 based on the latest kernel code. - From Thomas, split patch #1 into two. The new patch #1 converts kstat_irqs into a struct with just the count in it; the new patch #2 introduces a snapshot mechanism for interrupt statistics. Due to the code being split, I removed the Reviewed-by tags from LiuSong and Douglas in patch #1 and patch #2. Please review it again, and all comments are welcome. - Revised the comment for using printk() instead of pr_crit() to make the reasoning clearer. Changes from v11 to v12: - From Douglas and Thomas, add a new kconfig knob save memory when the softlock detector code is not enabled. - Adjust the order of the patches; patch #1 and patch #2 are related to genirq, while patch #3 and patch #4 are related to watchdog/softlockup, making the dependency relationships clearer. - Add the 'Reviewed-by' tag of Douglas. Changes from v10 to v11: - Only patch #2 and patch #3 have been changed. - Add comments to explain each field of 'struct irqstat' in patch #2. - Split the inner summation logic out of kstat_irqs() and encapsulate it into kstat_irqs_desc() in patch #3. - Adopt Thomas's change log for patch #3. - Add the 'Reviewed-by' tag of Liu Song. Changes from v9 to v10: - The two patches related to 'watchdog/softlockup' remain unchanged. - The majority of the work related to 'genirq' is contributed by Thomas, indicated by adding 'Originally-by' tag. And I'd like to express my gratitude for Thomas's contributions and guidance here. - Adopt Thomas's change log for the snapshot mechanism for interrupt statistics. - Split unrelated change in patch #2 into a separate patch #3. Changes from v8 to v9: - Patch #1 remains unchanged. - From Thomas Gleixner, split patch #2 into two patches. Interrupt infrastructure first and then the actual usage site in the watchdog code. Changes from v7 to v8: - From Thomas Gleixner, implement statistics within the interrupt core code and provide sensible interfaces for the watchdog code. - Patch #1 remains unchanged. Patch #2 has significant changes based on Thomas's suggestions, which is why I have removed Liu Song and Douglas's Reviewed-by from patch #2. Please review it again, and all comments are welcome. Changes from v6 to v7: - Remove "READ_ONCE" in "start_counting_irqs" - Replace the hard-coded 5 with "NUM_SAMPLE_PERIODS" macro in "set_sample_period". - Add empty lines to help with reading the code. - Remove the branch that processes IRQs where "counts_diff = 0". - Add the Reviewed-by of Liu Song and Douglas. Changes from v5 to v6: - Use "./scripts/checkpatch.pl --strict" to get a few extra style nits and fix them. - Squash patch #3 into patch #1, and wrapp the help text to 80 columns. - Sort existing headers alphabetically in watchdog.c - Drop "softlockup_hardirq_cpus", just read "hardirq_counts" and see if it's non-NULL. - Store "nr_irqs" in a local variable. - Simplify the calculation of "cpu_diff". Changes from v4 to v5: - Rearranging variable placement to make code look neater. Changes from v3 to v4: - Renaming some variable and function names to make the code logic more readable. - Change the code location to avoid predeclaring. - Just swap rather than a double loop in tabulate_irq_count. - Since nr_irqs has the potential to grow at runtime, bounds-check logic has been implemented. - Add SOFTLOCKUP_DETECTOR_INTR_STORM Kconfig knob. Changes from v2 to v3: - From Liu Song, using enum instead of macro for cpu_stats, shortening the name 'idx_to_stat' to 'stats', adding 'get_16bit_precesion' instead of using right shift operations, and using 'struct irq_counts'. - From kernel robot test, using '__this_cpu_read' and '__this_cpu_write' instead of accessing to an per-cpu array directly, in order to avoid this warning. 'sparse: incorrect type in initializer (different modifiers)' Changes from v1 to v2: - From Douglas, optimize the memory of cpustats. With the maximum number of CPUs, that's now this. 2 * 8192 * 4 + 1 * 8192 * 5 * 4 + 1 * 8192 = 237,568 bytes. - From Liu Song, refactor the code format and add necessary comments. - From Douglas, use interrupt counts instead of interrupt time to determine the cause of softlockup. - Remove the cmdline parameter added in PATCHv1. Bitao Hu (5): genirq: Convert kstat_irqs to a struct genirq: Provide a snapshot mechanism for interrupt statistics genirq: Avoid summation loops for /proc/interrupts watchdog/softlockup: low-overhead detection of interrupt storm watchdog/softlockup: report the most frequent interrupts arch/mips/dec/setup.c | 2 +- arch/parisc/kernel/smp.c | 2 +- arch/powerpc/kvm/book3s_hv_rm_xics.c | 2 +- include/linux/irqdesc.h | 16 +- include/linux/kernel_stat.h | 8 + kernel/irq/Kconfig | 4 + kernel/irq/internals.h | 4 +- kernel/irq/irqdesc.c | 50 +++++-- kernel/irq/proc.c | 9 +- kernel/watchdog.c | 215 ++++++++++++++++++++++++++- lib/Kconfig.debug | 14 ++ scripts/gdb/linux/interrupts.py | 6 +- 12 files changed, 302 insertions(+), 30 deletions(-)